Advanced positioning and tactics

This advice does not talk about specific locations or tricks that will help you during trivial moments. This information is beneficial for those who want to play better in the long run.

When you're in the battle field, you must take these things into consideration if you want to gain the advantage.

Location: where you are, where your team mates are at, your opponent's location, and where you can go.
Weapons: what kind of weapon your holding, and what weapons your enemies are holding.
Shield: how much damage you and others can receive.
Weapon Spawns: the chances of a target or ally being at a specific weapon spawn.
Hot-spots: locations where targets are most likely to be.
Field of View: areas where you, your team, and your opponents are likely to be looking at.
Skill: the ability and movement style of yourself and all other players in the game.
Chance: placing your cross-hair where you feel someone is most likely to appear, to decrease the time and the distance you have to drag your reticle to aim at your target.
All these things are important when getting killed isn't what you have in mind. And it will certainly be to your advantage if all this information is being calculated through your instincts/sub-consciousness.

Knowing these things will help you determine safe paths so that you can go from point-A to point-B without getting killed in the process. And more importantly, knowing this information will help you exploit your enemies' weak points. No one is invincible, no matter how good they are. They are just very good at exploiting your weaknesses to their advantage.

Know Your Location
As much as possible, work to discover your opponent's location. Assessing your options, whether your location is out of your opponent's field of view and what kind of weapon your opponent has will inform you whether you have the advantage. Know as much as you can, whether by communication or observation. If you know you are at a disadvantage, don't open fire unless you have a specific purpose for doing so. You won't get every kill just because you made the first shot. Be sure you can kill your target before you expose yourself to your opponent or his or her entire team. If they are good, they will pass your location to each other and trap you!

When you decide to move, chances are you will run into what looks like an uninhabited location. Don't do this without thinking; someone may be setting a death trap for you. Look at your team mates, or other players in the game. Think about who could be where. Listen for gunfire, and keep an eye out for movement. You don't want to give the opposition a free kill by walking into the open because you made a clumsy mistake. A spot is only safe if you make it safe.

The best team work advice I can give you that has not been said is flanking and trapping. It is unbelievable how many times this has saved my life. Flanking would be going up to someone who is least expecting your company. Like someone on your team trying to kill someone, but he is almost dead, so you come up behind the enemy. Trapping is also very good. Some players, however, are very smart and know when to avoid this. Still, most players won't see it coming. An example of this is luring an enemy back and then having someone on your team come out from behind a corner. Using both of these moves can lead to an easy victory. For example, one time I was playing on Guardian with one of my friends. Coming from the center was an enemy. He went into a base to kill my teammate and I went up behind him and killed him. Then, the enemy's teammate went in because he saw me go in. I lured him in, my teammate crouched near the entrance with a shotgun so when he came in he shot him with the shotgun. Two kills, no deaths, excellent teamwork. BTW the game ended 25 to 6 and we won. We kept using those tactics. -TreeFiddy350